In 2010 I comissioned James Harvey to see what he could with the basic concept. I love his "eyeball striding o'er the land" so much, and have used it for my main site, for business cards, and as a custom iPhone case:
In 2011 Madam Luna announced she was taking commissions, so gave her a shot... I like the Disney/Osamu Tezuka vibe.
In 2013 I crowdsourced an Alien Bill Logo design, as an experiment, and because I wanted something that would look good on an app. This was audentia's winning result:
Later in 2013 I had Harvey James do another Alien Bill as a sweetener for a book collaboration we are doing, again I like wht he did with the guy... less iconic, but "Alien Bill Running" has kind of been done to death anyway...
Along the same lines, and same level of obscurity, was a kind of keen video game called "Lunar Leeper"-- it wasn't a terribly deep game, but I like how these guys would bop around and then suddenly leap to grab the player's craft:
Of course, it has been pointed out that there may have been a shade of Ralph Waldo Emerson's
transparent eye-ball... I remember seeing this parody or homage of it in high school, but it may have been after i started drawing Alien Bill.
Finally, the main guy I will probably always be thought of as ripping off is Mike Wazowski from Monsters, Inc, though he postdates Alien Bill by at least 5-10 years.
Interesting, all the influences of Alien Bill lacked arms... and while the current Mike Wazowski takes it the other direction by adding a mouth (and horns and claws) "In an early animation test, Mike was considered to have no arms and would have picked things up with his feet." (source)